They're different because the antis want to ban them?
Perhaps you think it's nuts to agree to sell a gun to a complete stranger without any background check. That's fine. I'm not interested in arguing over how you want to do your sales. Some folks just feel better if they go through an FFL and get a NICS check on every one. That's OK.
When I first read your post, it kinda sounded, perhaps because I read it too quickly, that you don't think anyone should be allowed to sell a gun to a stranger without a background check or an FFL. My apologies if I was mistaken.
I'm a lawyer, but I'm not your lawyer. If you need some honest-to-goodness legal advice, go buy some.